Asset management companies are seeing profit margins squeezed as growing numbers of investors flock to “passive” funds — portfolios which mirror a market index, rather than try to outperform it as active fund managers do.

That shift is being driven by record low interest rates and depressed global growth in the wake of the financial crisis, which has made market out-performance increasingly difficult. The FT reported last year that 99% of actively-managed US funds had failed to beat their benchmark since 2006.